It is highly desirable to be able to minimize the amount of service required for internal combustion engines to thereby minimize the interruption in the use of the vehicle/equipment. Degradation and contamination of engine lubricating oil during engine use requires oil-changing procedures that account for a significant portion of the maintenance and associated engine down time. Conventional periodic oil changes generate an accumulation of waste lubricating oil that must be disposed of and/or processed resulting in undesirable costs.
Therefore, extending oil drain intervals and reducing waste disposal are of great value to vehicle/equipment operators. Consequently, systems have been developed for automatically changing internal combustion engine crankcase oil during engine operation.
One example of a conventional system automatically changes engine oil while the engine is operating. The system operates to drain substantially all of the used oil from the engine immediately prior to introducing fresh oil into the engine from a reservoir. The operation process results in a complete change of substantially the entire engine oil volume.
However, draining the engine prior to refilling with fresh oil necessarily creates a risk that an inadequate supply of lube oil exists in the engine for an interim time period possibly resulting in damage or excessive wear to engine components from insufficient lubrication. Moreover, this conventional system undesirably results in a quantity of waste oil.
Another example of a conventional system automatically changes engine lube oil during engine operation while avoiding a waste quantity of oil by directing the used lube oil into the fuel system for burning with the fuel in the engine. This example periodically drains a small amount of the used oil from the engine lube oil system and replaces the drained quantity with fresh lubricant from an auxiliary tank.
There are many drawbacks with conventional systems. One example of a drawback is that the oil removal control of some conventional systems could fail to precisely control crankcase oil removal rates, leading to the removal of too much crankcase oil too quickly, resulting in engine failure on the highway.
Another drawback is that some conventional systems do not regulate the amount of crankcase oil that is fed to the fuel tank in accordance with the fuel level in the tank, thus the ratio of crankcase oil to fuel may be too much or two little relative to the ideal ratio. In particular, too much oil in a fuel tank that is not significantly full can result in excess hydrocarbons in the vehicle exhaust, thus contributing to air pollution. Moreover, the addition of crankcase oil to the fuel tank depresses the vapor pressure of the fuel in the tank, thus starting an engine can be more difficult, particularly in cold weather
Other conventional systems utilize expensive pumps, control systems and auxiliary waste oil storage tanks, thus decreasing cost effectiveness that tends to discourage widespread implementation.
Lastly, many conventional systems fail to recover the waste oil energy in the oil filter, thereby not resolving the landfill problem of oil seeping from such filters.
In summary, these conventional approaches fail to take care of the used crankcase oil problem in a satisfactory manner. These conventional methods fail to recover the full value inherent in waste oil and oil filters; require consumption of extra energy and material resources; and add to the size of the environmental problem associated with used engine oil.
Therefore, it is desirable to provide a system that effectively utilizes all the resources of used crankcase oil in a satisfactory manner. Moreover, it is desirable to provide a system that recovers the full value inherent in waste oil and oil filters and/or does not require consumption of extra energy and material resources to dispose of the used oil. Furthermore, it is desirable to provide a system that reduces or effectively addresses the environmental problem associated with used engine oil.